private void ComputeLod(Node root, double k, EntityManager entityManager)
{
var mesh = entityManager.GetComponent<StaticMesh>(root.Entity);
var side = (root.Bounds.Max - root.Bounds.Min).X;
var radius = Math.Sqrt(side*side + side*side);
for (int i = 0; i < 6; i++)
{
if (PlaneDistance(_frustumPlanes[i], root.Bounds.Center) <= -radius)
{
return;
}
}
var error = root.GeometricError;
var distance = (root.Bounds.Center - _camera.Position).Length;
var rho = (error / distance) * k;
var threshhold = 100;
if (rho <= threshhold || root.Leafs.Length == 0)
{
mesh.IsVisible = true;
}
else
{
for (int j = 0; j < root.Leafs.Length; j++)
{
ComputeLod(root.Leafs[j], k, entityManager);
}
}
}
public void Update(double elapsedTime, EntityManager entityManager)
{
if (_root == null)
{
_root = CreateNode(new Box3D(new Vector3d(-100, 0, -100f), new Vector3d(100f, 0, 100f)), 6, entityManager);
}
_frustumPlanes = FrustumPlaneExtractor.ExtractRowMajor(_camera);
var k = _camera.Width / (Math.Tan(_camera.HorizontalFieldOfView / 2));
ComputeLod(_root, k, entityManager);
}
public Node(Box3D bounds, Node[] leafNodes, Entity entity, double geometricError)
{
Entity = entity;
GeometricError = geometricError;
Bounds = bounds;
Leafs = leafNodes;
}